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Topic Review (Newest First)

09-13-2005 02:27 PM

lt1bbody

I adjusted the carb and it idles a lot smoother and the car is actually driveable . I'm going to change the plugs and hope the slight miss and popping from the pass side exhaust stops. I have ACdelco R44T plugs. What should I get for a hotter plug? I'm also running 76cc heads and about 9:1 compression.

09-10-2005 03:28 PM

lt1bbody

The carb I have is an Edelbrock Performer 600cfm. I have ACDelco plugs but I don't know what the number is off hand. The plugs I bought were for a 72 chevy pickup (got from the casting numbers). I just rebuilt it and the car was running OK after the rebuild. To make the mixture screws bottom out wouldn't you have to really crank them down tight. I put mine in all the way just until it got snug. I'll try new plugs and adjusting the carb. I'll get back to you on it. I'll like the detailed write up on adjusting the carb.

09-10-2005 05:53 AM

docvette

induction system

Doc here ,

Q~jet or TBI or TPI fuel infection..?(<---miss spell but I like it so it stays..) I thinkin' Q~jet?

If so, Clean the carb with spray carb cleaner, inside and out, spray all the ports , nooks and cranny's that you can get to....use 2 or even 3 cans if necessary, soak it good on the car, let it dry, ...then adjust the idle jets..

Warm the car, make sure the choke is wide open, set idle 750 man 950 auto, and CAREFULLY turn the Idle screws in until the engine stumbles and dies..

back it out 6, 1/2 turns (easier to count) or 3 full turns and re start, do the same on the other side..

DO NOT BOTTOM either of these out!!
They are brass and will scar and will then no longer be useful at all..

Restart and working SLOWLY, chose a jet, and turn it in about 1/8 of a turn at a time until you get the highest idle, wait about 5 to 10 seconds for the engine to normalize before turning again , If you don't you'll adjust right through the "Sweet Spot"..

Do the same for the other side...

Now,..SLOWLY using small turns , and waiting 10 to 30 seconds between adjustments..work between the two first right then left, your going for Highest idle, no random stumble or "Pop'

When you feel you have maximized the adjustments, go to the rear...what do you smell? SHOULD be nothing if you did it right...

If the idle jets have No effect when you turn them in..think new carb or rebuild this one, as this one is at runout...

Doc

09-09-2005 07:20 PM

poncho62

I think that I would try new plugs.......what plugs do you have in it?

Maybe you want a hotter plug.

09-09-2005 07:12 PM

lt1bbody

I got the grease for the module from the parts store and put it all back together. I also checked the plugs and they had a lot of carbon on them. I cleaned them up and put them back in to see if there was any noticeable difference. The car still misses but after I turned up the idle enough so it would run on its own (So I could check thigs out)the idle was noticeably better. The car revs a lot smoother too. I then checked the plus and they are all carboned up again. I can also hear it missing on the left bank through the exhaust. The exhaust has a raw fuel smell. The car ran fine after the trans swap. It just started acting up a couple weeks ago. The car is a 85 Monte Carlo with a TH250.

09-09-2005 02:16 PM

T-bucket23

Quote:

Originally Posted by lt1bbody

I had the module tested and it passed he checked 5 times. Under where the module is there is a white buildup like oxidation can this cause the engine to run rough or not at all? I'm going to check all the wires and connections under the cap, clean off the oxidation, put some new lithium grease under the module and put it back together to see what happens. I'll post once I do this as long as it doesn't rain today.

That "white build up " is thermal transfer grease and is supposed to be there. It helps to cool the module while still alowing an elecrical connection. If you dont put some on the module and plate you will be replacing the module soon.
Dont use lithium graese, get the proper grease from the parts store or a Radio Shack, either should have it. It usually comes in a little syringe type applicator.

09-09-2005 01:51 PM

T-bucket23

bad Idle

Sounds like a vacuum leak. My guess is you either broke or didnt re-connect the vacuum line to the modulator after the tranny work. have you tried a vacuum gauge to see what it reads. I think you need to start from the begining. If the wires were arcing they are bad or the wrong wires. Make sure you have a good set to start with. I would also replace the plugs, they are fairly cheap and also can not be completly ruled out with just a visual inspection. Assuming the car ran ok before you pulled the tranny, you need to look at what could have happend during that procedure and for gods sakes stop throwing parts at it.
More info would be helpfull also, what year, what tranny etc

09-09-2005 01:25 PM

Velyx21

hmm maybe ur plugs are carboned up really bad.. ??

09-09-2005 12:53 PM

lt1bbody

I cleaned everything real well and checked all the wires. no breaks loose connectors ect. I guess I'm going to buy a new module because I just don't know what else there is to check everything seems to be ok

09-09-2005 11:15 AM

lt1bbody

I had the module tested and it passed he checked 5 times. Under where the module is there is a white buildup like oxidation can this cause the engine to run rough or not at all? I'm going to check all the wires and connections under the cap, clean off the oxidation, put some new lithium grease under the module and put it back together to see what happens. I'll post once I do this as long as it doesn't rain today.

09-09-2005 04:01 AM

docvette

Module

Doc here,

Pull the module and take it to the local auto parts store..They can test it for you free..

If it is bad ,and you get a new one, Have that one tested too...THE OBF rate on those is about 1 in 3...and once you leave the store it's your problem..make sure they test it several times to heat it up.

When re installing the old one or installing a new one..DON"T FORGET The Silicone heat sink grease..without it you'll be doing it again in a few weeks. Clean all the old stuff off, and generously but not sloppy, apply to the module, and a just a dab to the advance plate.

Make sure module wires aren't shorting to anything and have movement with the advance plate..Inspect the Magnetic pickup while your in there and make sure there are no metal shavings sticking to it.

BAD PLUG WIRES are major contributers to the premature failure of Modules, because they set up a high tension RFI that back feeds into the dizzy and blows the ECM substrate apart...So anymore mis fires are not the only consequence of running with "BAD WIRES" until payday...

Doc

09-08-2005 05:15 PM

steve t

when a module go bad it want crank, you may have crossed wires

09-08-2005 03:46 PM

lt1bbody

I changed to some new wires and now the engine won't even stay running ( i first changed just the #2 cylinder wire then all). I'm thinking there is a problem with the ign. module because it is pretty warm out today and is really sunny causing a lot of heat under the hood. Last night it was running ok and was idling ok even with the #2 cylinder arching. Is there a way I can check the module to see if it is bad?

09-07-2005 10:51 PM

lt1bbody

I just checked the wires doing what 73oldsman said and found it arching to the block on the #2 cylinder. I'll get some new wires for it tomorrow and tell you what happens. I didn't think the wires could be bad since they are new, but from taking them off and on as many times as I did from all the misc. problems I had with the engine: dist 180 off, no oil to left bank (cam bearing problem), I guess the wires get worn out quick. I'm glad that I'm having all these problems now being that it is the first engine I built. It will be easier for me to solve similar problems in the future. Thanks.

09-07-2005 12:27 PM

Velyx21

sounds like bad plug wire someewhere, my car had the same symptoms. Popped one of the plug wires and boot was brittle and cracked open, it was arcin to the header.

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